docs: def _get_linear_site_term(self, C, vs30):
          """
          Returns the linear site scaling term (equation 6)
          """
          flin = vs30 / self.CONSTS["Vref"]
          flin[vs30 > C["Vc"]] = C["Vc"] / self.CONSTS["Vref"]
          return C["c"] * np.log(flin)